Fuel stoker



n FUEL sToKER Filed Jan. 21, 1933 2 Sheets-Sheet l 9 47 g 9, 3/ I I I l .y wvento 47 fff Raw/1 ../Ve/son 227.5 @a 38 l a, MMX-7% Fem-1935. R, L. NgLSON f 1,990,086

FUEL STOKER Filed Jan. 21, 1933 2 {Sheets-shew:l 2

@im 9 Mfg/x Patented Feb. 5, 1935 PATENT OFFICE' FUEL STOKER.

Ralph El. Nelson, Spokane, Wash.

Application January 21,

(Cl. 11o-32) 1 Claim.

My invention relates to fuel stokers that are adapted to convey fuel, such as pulverized coal or the like, by means of a helical orwormed conveyor from a hopper to a burner retort. Certain objects of the invention are to provide a stoker comprisinga new form and arrangement -of tuyre members for the burner retort, a new arrangement, location and mounting for the draft turbine and motor, a new transmission and means for driving the worm fuel conveyor,

a new arch breaker Within the hopper for feeding fuel to the worm conveyor, and a number of othernovel details of construction, arrangement and mounting as more fully hereinafter With the above and other objects in view which will appear as the description proceeds, the 'invention consists of the novel construction, adaptation, combination and arrangement hereinafter described and claimed. These objects are accomplished by devices illustrated in the accompanying drawings; wherein: Figure 1 is a general view in exterior perspective of the stoker; Fig. 2 is a top plan view of the same with parts broken away; Fig. 3 is a detail view in perspective showing one ofthe tuyre members of the burner retort; Fig. 4 is a view in vertical section through the burner retort' taken on a broken line 4 4 of Fig. 1; Fig. 5 is a view in longitudi- '30 nal vertical section through a portion of the hopper and transmission housing and taken on a broken line 5-5 of Fig. 2; Fig. 6 is a detail view inperspective showing the draft control casing and its shutters; Fig. 7 is a view in transverse vertical section through the transmission taken on a broken line 7--7 of Fig. 2; Fig. 8 is a view in transverse vertical section' taken on a broken line 3,-8 of Fig. 2` and showing the motored fan and associated parts; Fig. 9 is a view in transverse vertical section taken on a'broken line 9-9 of Fig. 2 and showing the arrangement within the hopper trough for agitating the pullv"erized,f uel; and Fig. 10'.is a fragmentary viewA in vertical section showing a modified tuyre. ar-

5 rangement.V y

Referring in detail to the drawings throughout which like reference numerals indicate like parts, the numeral 5 designates the burner retort tuyre-structure which is made up in cylindrical form by uniting a number of tuyre members 6, such as shown in Fig.3 of the drawings,

and securing them together by means of a metal..

band 7 as shown in Figs. 1, 2 and 4. 'I'he tuyre members are hollow, as at 8, and have aA number of apertures 9 communicating with the 1933, Serial No. 652,841

interior of the retort as will'be understood. The base 10 of th retort is also hollow, as at 11, and its interior t p portion is secured tothe interior bottom portion ofthe tuyre-structure by means of a rabbet'joint 12. Said base is provided .with 5 an air entry port or mouth 13, as clearly shown in Fig. 1, and air entering through same passes through the chamber 11 of the base and upwardly through the chamber 8 of the tuyre structure and thenceinwardly through the aper- 10 tures 9 to provide a draft for a re within the retort. It-l will be noted that the lower inner surface of the tuyre members slant inwardly in conformity with the convergent interior of the base 10,- and that the upper inner surface 15 of said members having the apertures is vertical. It is preferable to slant the apertures 9 slightly upward in the outside direction and the foregoing arrangement provides draft means whereby fuel ofa low burning point may be readily go consumed withoutpermitting molten masses or ash to run into the draft conduits. Referring to Fig. 10,'the modied form of tuyre members 6 is provided with an aperture 14 extending entirely through and above the usual apertures '25 9, and said aperture 14 is in communication with the interior of the tuyre members. Said members are provided with an annular shoulder 15 to which an outside plate 16 is fastened. This plate extends all the way around the burner re- 30 tort and its purpose is to catch any pulverized fuel that might be carried over the top wall of the retort. The aperture 14 provides a draft so that any such overow fuel will continue to burn on'the outside.

Draft is furnished through a blast lconduit 17 v that is connected to the mouth 13 of the base of the retort 5, and a fan 18, encased in a housing 19 connected to the other endl of said conduit, provides' the draft. Said conduit is provided 40 with an oiset having a door at 20 whereby the conduit may be cleaned out. The fan is driven bya motor 21, and the fan housing 19 has a draft control casing 22 connected to' its side,

and communicating therewith, and a plurality I of shutters 23 are suspended von rods 24 that are.

"pivotally mounted'across the open outside endof the housing. Saidl lshutters overlap each other on the inside andare made of canvas or other stiff fabric so that they are noiseless in 50' their operation. These shutters are normally closed by their own weight. When the nre within the retort dies. down whereby a thermostat (not shown) starts the motor and rotates the fan air is suckedin through the shutters of the u adapted to catch casing causing them to pivotally swing open, as shown in dotted lines in Fig. 8, and when the fire gets hot the thermostat will shut off the motor whereby the shutters will again swing to the closed position. As shown in Figs. 2 and 8, the motor 21 is mounted on a bracket shelf 25 that is fixed to the fan housing 19 and slidably disposed on a platform 26 which platform is xed to the fuel conveyor tube 27. The discharge end of the fan housing telescopes into the inner end of the blast conduit 17 at 28 and it will thus be.

seen that the motor, fan and its housing may be slidably moved back and forth as a unit for the purpose of tightening an endless V-belt hereinafter set forth. A iiexible pipe 29 has its ends connected to the fan housing and to the conveyor tube 27 whereby some of the draft from the fan is utilized in preventing smoke or dust from backing up from the retort through the conveyor tube. The particular location of the fan 18 and motor 21 forward of the coal'hopper, hereinafter described, is a very important feature of my` invention as `it makes possible the use of a very short conduit 17 through which air is delivered to the burner retort at a maximum velocity.

The outer end of the conveyor tube 27 communicates with the interior of the burner retort 5 and is connected at-30 to its base 10 as shown in Figs. 2 and 4. The inner end of said tube is connected to the trough or base portion 31 of a hopper 32. Said base of the hopper has a rear extension shelf 33 and a transmission housing 34 is mounted thereon as shown in Fig. 5. The shaft of the motor 21 is provided with a detachable pulley 35 and an endless V-belt 36 extends fromsaid pulley to a detachable pulley 37 mounted on the outer end of a, Worm shaft 38 which shaft extends into the transmission housing 34. 'I'he worm portion of said shaft meshes with a worm gear 39 which'is fixed on'another worm shaft 40 the worm portion of which meshes with a large worm gear 41 fixed on a tail shaft 42 that is centrally journaled through the transmission housing 34. Said large worm gear is fixed on' said tail shaft by means of a shear pin 43 so that any clogging or stopping of the mechanism will result in a rupture of the shear pin and thus further damage would be prevented. A roller thrust bearing 44 is provided for the large worm gear, and, it being understood that the transmission housing is to be partly filled with oil, a chain 45 is revolubly carried by the tail shaft for the purpose of lifting some of the oil and thus lubricating the bearings of said shaft. A trough 46 is arranged in near. engagement with the upper portion of the large gear 41 and is and convey some of the oil lifted by said gear to the `upper bearing of the worm shaft 40. The transmission housing is provided with the usual screw plugs for the purpose of filling, draining and maintaining the proper oil level. It will be apparent that either ofthe pulleys 35 or 37 may be changed for others of different size for the purpose of altering the speed of the foregoing described mechanism.

The forward end of the tail shaft 42 is square in cross section and fits into a corresponding slot through said trough and forwardly.v through the conveyor tube 27, which serves as a bearing therefor, and into the burner retort 5. It will now be apparent that the motor 21, by means of the foregoing described mechanism, causes slow rotary movement of the conveyor worm whereby pulverized fuel within the hopper 32 and its trough 31 is carried -forward into the burner retort. For the purpose of agitating the fuel within the hopper and trough and causing it to Work down freely into engagement with the worm conveyor, I'

have provided an arch breaker comprising a wheel 50 having studs 5l around its periphery as shown in Fig. 9. Said studs are so spaced apart as to properly engage the worm flange of the conveyor whereby the Wheel will be rotated by said worm conveyorA as will be understood. In addition to said studs, a pair of spurs 52 are fixed to the wheel at opposite points and project outwardly therefrom. The hub of said wheel is journaled in upstanding bracket bearings 53 that are fixed to the bottom of the hopper trough and is retained in position by nuts 54. The slow rotary movement of said wheel causes the fuel to move to the bottom of the trough where it is carried out by the worm conveyor.

While I am aware that fuel stokers have been patented prior to my invention, I am not aware that my particular arrangement of tuyre members forming the burner retort, or the detail V.transmission means for slowly driving the Worm conveyor together with the means for agitatively feeding fuel within the hopper to the worm conveyor, nor the locaion and mounting of the motor and turbine and the construction of associated parts 4including the automatic draft lcontrol, or the many other details of construction have heretoforebeen devised.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is VIna fuel stoker, a fuel supporting structure having a fuel inlet and an air inlet, a fuel hopper spaced from said structure and having a conduit extending therebetween, a fixed platform mounted over said conduit, an air conduit extending longitudinally of the fuel conduit with its front end communicating with the air inlet of said structure, a fan housing having discharge means telescoped into the rear end of the air conduit, supporting means secured to said fan housing and adjustably supported upon said platform, a motor operatively connected to said fan housing and supported upon said supporting means and extending transversely of the hopper and fuel conduit, means for feeding fuel from said hopper through the fuel conduit having operating means including a driving shaft spaced from the motor longitudinally of the hopper, and a -driving belt interconnecting said motor and driving shaft.

RALPH L. NELSON. 

